Many implanted cardiac devices monitor the electrical activity of the heart for tachyarrhythmias. An implanted device typically classifies the tachyarrhythmia, i.e., identifies or discriminates the form of tachyarrhythmia. Discrimination is important because some tachyarrhythmias are life threatening and some are not. In addition, the implanted device may apply a therapy to treat the tachyarrhythmia, and discrimination is important to applying an appropriate therapy.
One form of tachyarrhythmia is referred to as supraventricular tachycardia (SVT) with 1:1 atrial to ventricular conduction (AV conduction). SVT with 1:1 AV conduction includes atrioventricular node reentrant tachycardia, atrioventricular reentrant tachycardia (also called Wolff Parkinson White Syndrome), and other atrial tachycardias that may be automatic, triggered, or reentrant.
Some forms of SVTs are referred to as >1:1 AV conduction, meaning that the number of atrial activations exceed the number of ventricular activations. Therapies used to treat 1:1 SVTs may be different from therapies used to treat >1:1 SVTs. Atrial anti-tachycardia pacing, for example, may be relatively safe for treating >1:1 SVTs, but may be more risky for a 1:1 SVT.